Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 4, 2009
Publication Date: June 5, 2009
Citation: Hunter, W.B., Hert, M.M., Sinisterra, X.H., Hall, D.G., Katsar, C.S., Powell, C.A. 2009. Reovirus-like sequences isolated from adult Asian citrus psyllid, (Hemiptera: Psyllidae: Diaphorina citri). Florida Entomologist. 92:314-320. Interpretive Summary: We discovered an insect-infecting virus in adult Asian citrus psyllids in Florida. The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is a small insect that feeds on the sap of citrus trees and is the primary vector of the plant pathogenic bacterium, Candidatus Liberibacter asiaticus, which causes Huanglongbing, HLB, also known as Citrus Greening. The bacterium, which was recently discovered in Florida, causes severe economic losses to citrus reducing fruit yields and making the fruit taste bad. To identify new biological control agents in psyllid populations we examined the genetic sequences from adult psyllids collected from citrus trees. We identified a new insect virus which was similar to the insect-infecting Reovirus group. Comparison of the virus gene sequences indicated that the virus is in the Family: Reoviridae, Genus: Fijivirus, described from planthoppers a closely related insect group. Though wide spread in nature, this is the first report of a Fijivirus in North America. We are conducting further tests to determine if this new virus will help to reduce psyllid populations and the spread of citrus greening through its use as a biological control agent.
Technical Abstract: Though wide spread in nature, this is the first report of a Fijivirus from North America and which was detected in a new virus host species, the Asian citrus psyllid. Few viruses have ever been reported from psyllids. We discovered an insect infecting virus in field collected Asian citrus psyllids in Florida. The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is a small insect that feeds on the phloem sap of citrus trees and is the primary vector of the plant pathogenic bacterium, Candidatus Liberibacter asiaticus, which causes Huanglongbing, HLB, also known as Citrus Greening, due to discoloration of fruit. The bacterium causes severe economic losses to citrus industries worldwide and has recently been identified in Florida, 2005. Traditional control measurements of the psyllid, which was discovered in Florida in 1998, have proven to be ineffective and costly. Biological control measurements provide environmentally friendly management tools of insect pests. We examined an expression library prepared from adult psyllids in search of new pathogens. We identified two viral sequences, of 890 and 1050 base pairs respectively, both of which had significant similarity to viruses within the insect Reovirus group. Phylogenetic and homology comparisons using BLASTX, BLASTP and PAUP analyses indicated that the viral sequences were closely related to the viruses in the Family: Reoviridae, Genus: Fijivirus, specifically Nilaparvata lugens reovirus (NLRV) described from planthoppers a closely related group of insects within the Hemiptera. Insect reoviruses are transmitted by delphacid planthoppers in a circulative propagative manner. This is the first report of a Fijivirus occurring outside of its reported vectors, planthoppers. Further survey efforts aim at detecting reovirus-like sequences in different psyllid population, as well as molecular characterization of the viral genomes, and insect pathogenicity test which are needed to explore the possible uses of Reovirus as a biological control agent of psyllids and other Hemipterans.